A variety of techniques are available for affixing objects such as soft tissue to bone. The oldest technique utilizes thread passed through the bone and the tissue to sew the tissue down to the bone. Many sizes, shapes and types of suture and suture needles are available to accomplish this task. Today, this method is still used for repair of tendons and ligaments in older osteoarthritic patients, although passing a suture through bone is generally difficult and tedious.
Soft tissue repairs also have been accomplished with metal screws or staples that attach soft tissue to bone. Metal screws and/or staples are, however, subject to corrosion and consequent loss of structure. Moreover, the presence of metal in an anatomical site can interfere with imaging and diagnostic or therapeutic treatments near the site. For example, any metal implants may have to be removed by surgery prior to magnetic resonance imaging. Patient sensitivity to nickel ions and stainless steel implants has fueled a growing controversy regarding the use of materials containing high quantities of nickel including nickel-titanium alloys such as Nitinol. Also, it is almost impossible to adjust the compression exerted by screws and staples on soft tissue. Thus, these devices are not fully satisfactory for soft tissue repair.
Other devices employ a suture anchor installation affixed to an arc of wire or a plurality of barbs disposed on an outer surface of the suture anchor body. The barbs or arc of wire are set by applying traction to the suture. Unfortunately, it is not always possible to position the anchor at a precise location within a bone if an anchor is being drawn upwards in a bone hole by applying tension to a suture. Furthermore, many of the fastening devices require some type of impact or impulse to set the fastener in position. Impact emplacement or setting of bone/suture anchors may result in injury to the patient as well as placing unnecessary strain on the bone/suture fastener itself.